CN1843051B - Systems and methods for using geographic location to determine when to exit a current wireless communication coverage network - Google Patents

Abstract

A system and method for determining when to exit an existing wireless communication coverage network is provided. The method samples the device geographic location, determines a threshold boundary line, measures the location of each sample point relative to the threshold boundary line, and, starting from a predetermined initial value, maintains a running total in response to measuring the location. The method uses a threshold boundary line to divide a coverage area of a current coverage network into a first area and a second area. The method then decreases the running total for sample point locations in the first region and increases the running total for sample point locations in the second region. The method exits the existing coverage network when the running total is greater than or equal to a predetermined terminal value and then resets the running total to a predetermined initial value.

Description

Systems and methods for using geographic location to determine when to exit a current wireless communication coverage network

technical field

The present invention generally relates to wireless communication devices, and in particular to a system and method for a wireless communication device communicating with a base station to determine whether the wireless communication device should stay in the current wireless communication coverage network.

Background technique

For wireless communication devices, the key issue is to obtain an overlay network with the best possible service level. The following discussion uses a Code Division Multiple Access (CDMA) network as an example, but it should be understood that the following discussion is applicable to other wireless communication networks. As a CDMA device approaches the edge of a CDMA coverage cell, the device begins operating at the boundaries of the CDMA network's forward link budget and/or reverse link budget and needs to determine whether to quit. Making an accurate decision when to leave the current cell is important because there are penalties for leaving too early or too late from the current wireless communication overlay network (hereinafter referred to as the current overlay network). Exiting prematurely would result in unnecessary loss of the preferred overlay system and may require a simulated overlay network due to a corresponding degradation in battery performance. Exiting too late may result in lost pages or missing the originator's call due to reverse link limitations.

It is known to allow the wireless communication device to remain in the current coverage area until the paging channel is completely lost. This approach often results in a late exit. Another known approach is to initiate exit processing when the device arrives at a predetermined location. To implement this approach, a base station (BS) or mobile switching center (MSC) creates a threshold boundary line or boundary area at a predetermined distance from the base station for the overlay network serving the device. Typically, the BS also determines the location of the device. When the device moves through the threshold line or enters the threshold area, it exits the current overlay network.

Figure 6 is a graphical representation showing the path of a mobile device through a current overlay network and neighboring overlay networks (Prior Art). Unfortunately, the threshold boundary line/zone approach described above can lead to premature exit from the current overlay network. That is, even when a wireless communication device comes back soon and stays in the original coverage network, a momentary excursion across the threshold line may cause the device to drop out of the current coverage area. For example, in Figure 6, when moving from point A to point B, the device exits network 1 and arrives at network 2, but a short time later, when moving from point B to point C and then onto point D, the device exits network 2 and re-reach network 1. Unfortunately, during each transition between overlay networks, data transfers can be impaired and drain excess battery power. In addition, whenever a device switches from demodulating one air-interface (Air-Interface) to another due to the above-mentioned conversion, the device must also reconfigure its resources to adapt to the new air-interface. This problem is exacerbated if the device is tossed or oscillated between overlay networks due to a series of rapid excursions across the threshold boundary line (eg, moving through point D to I in Figure 6).

In a CDMA cell, the satisfactory operating range (the air extent of the coverage area) and the location of the appropriate threshold boundary line therefore depend on the traffic within the cell. The base station noise floor may appear to increase as intra-cell traffic load increases due to inter-cell and intra-cell interference. As a result, the wireless devices in the cell must transmit additional power to overcome the increased interference, effectively shrinking the cell. Shrinking of a cell can move the area suitable for an overlay handoff closer to the center of the cell. Unfortunately, the threshold location is usually fixed, and it is not suitable to change the location for the area suitable for the coverage network.

It would be advantageous if a wireless communication device operating near a cell edge of a current overlay network could accurately determine when to exit the current overlay network, thereby avoiding premature and late exits.

It would be advantageous if a wireless communication device operating near a cell edge of a current overlay network could accurately determine when to exit the current overlay network, thereby avoiding oscillations between the current overlay network and neighboring overlay networks.

It would be advantageous if a wireless communication device operating near a cell edge of a current CDMA overlay network could dynamically modify parameters according to actual conditions in the network, thereby determining when to exit the CDMA overlay network.

Contents of the invention

The problem that the present invention is designed to solve is to determine when a wireless communication device operating near a cell edge of the current overlay network should exit the current overlay network. In the present invention, when to exit is determined by analyzing the distance between the base station and the wireless communication device. The present invention addresses this need by compiling a history of geographic location data for a wireless communication device, and exiting the current overlay network in response to the historical data of the device's geographic location data.

Accordingly, a method for determining when to exit a current wireless communication overlay network is provided. The method samples the geographic location of the device, determines a threshold boundary line, measures the position of each sample point relative to the threshold boundary line, and maintains a cumulative sum responsive to the measured position, starting from a predetermined initial value. The method divides the coverage area of the current coverage network into a first area and a second area by using a threshold boundary line. Then, the method increases the cumulative sum of sample point locations for the first region and decreases the cumulative sum of sample point locations for the second region. The method exits the current overlay network when the cumulative sum is greater than or equal to a predetermined final value, and then resets the cumulative sum to a predetermined initial value.

Additional details of the methods and systems described above for determining when to exit the current wireless communication overlay network are given below.

Brief description of the drawings

1 is a schematic block diagram illustrating a system for determining when to exit a current wireless communication coverage network;

Figure 2 is a graphical representation depicting a first threshold boundary line between a current coverage area and an adjacent coverage area and first and second areas;

Figure 3a is a graphical representation depicting a plurality of thresholds and regions between a current overlay network and an adjacent overlay network;

Figure 3b is a table listing the device locations shown in Figure 3a and the corresponding cumulative adjustments;

FIG. 4 is a flowchart representing a method for determining when to exit a current wireless communication overlay network;

Figure 5 is a flowchart further describing the method shown in Figure 4;

Figure 6 is a graphical representation showing the path of a mobile device through a current overlay network and neighboring overlay networks (Prior Art).

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT

1 is a schematic block diagram depicting a system for determining when to exit a current wireless communication coverage network. The system 100 in a wireless device 101 includes a locator 102 having an output in line 104 to provide a geographic sample location of the device, and a calculator 106 having an input connected to the line 104 . The calculator 106 can be implemented in software or hardware. In certain aspects, the output of locator 102 on line 104 periodically provides a geographic sample location of the device. Calculator 106 has an output on line 107 to provide an exit control signal responsive to the history of the device's geographic sample location and the first threshold boundary line.

Calculator 106 includes comparison circuit 108 and counting circuit 110 . Comparator circuit 108 includes an input coupled to the input of calculator 106 on line 104 . The comparison circuit 108 selects a threshold boundary line and, in response to receiving the geographic sample locations of the devices, measures the difference between each device's geographic sample location and the first threshold boundary line. In some aspects, comparison circuit 108 uses a look-up table (LUT) (not shown) in comparison circuit 108 to obtain information for selecting threshold boundary lines. In some aspects, the system 100 includes a transceiver 112 having an antenna port on line 114 for receiving threshold boundary line information transmitted from a base station (not shown) and an antenna port on line 116 for receiving An output of the threshold boundary line information is provided. In this regard, calculator 106 has an input on line 116 and comparison circuit 108 has an input connected to the input of calculator 106 on line 116 . Comparison circuit 108 uses the information received on line 116 to select a threshold boundary line. In some aspects, comparison circuit 108 stores information from the base station in the aforementioned LUT.

In some aspects, device 101 withdraws from the current network in response to an exit control signal on line 107 . In some aspects, device 101 exits from the current network in response to a command from a base station (not shown). In these respects, transceiver 112 includes an input coupled to the output of calculator 106 on line 107 and includes an output on line 117A; and calculator 106 includes an input on line 117A and an output on line 117B. Transceiver 112, in response to an exit control signal received on line 107, transmits a signal to a base station (not shown) for the current overlay network at its antenna port on line 114. The base station then determines whether device 101 should exit the current overlay network. The base station provides a command signal on line 114 to transceiver 112 if a decision has been made to exit the current overlay network. The output of transceiver 112 on line 117A provides the command signal and the output of calculator 106 on line 117B provides the base station exit signal in response to receiving the command signal on line 117A. Device 101 exits the current overlay network in response to the base station exit signal on line 117B.

Comparator circuit 108 includes outputs on lines 118 and 120, respectively, for providing a decrement control signal and an increment control signal, respectively, in response to the comparison. Counting circuit 110 includes inputs on lines 118 and 120, respectively. Counting circuit 110 performs a mathematical function in response to receiving a decrement control signal and an increment control signal, and compares the result of performing the mathematical function to a predetermined final value. Counting circuit 110 includes an output coupled to the output of calculator 106 on line 107 to provide an exit control signal in response to the comparison described above.

Figure 2 is a graphical representation depicting a first threshold boundary line between a current coverage area and an adjacent coverage area, and first and second areas. Figure 2 is not drawn to scale. The distance of the wireless device to the threshold boundary line between the current coverage network area and the adjacent coverage network area can be applied to the exit problem of the present invention. Although straight threshold boundary lines are shown in FIG. 2, it should be understood that other configurations, such as circular boundary lines, may also be used. The distance of the threshold boundary line to the base station can be chosen according to the desired system performance. One possible distance is the maximum distance to the base station associated with the forward and/or reverse link budget. That is, geographical sample locations of devices farther from the base station than from the threshold line indicate a tendency towards unsatisfactory operation, while locations between the threshold line and the base station indicate a tendency toward satisfactory operation. If the device is consistently positioned beyond the threshold boundary line, the device should exit.

The comparison circuit (reference numeral 108 in FIG. 1 ) selects the threshold boundary line to include at least a portion of the coverage area of the current overlay network and at least a portion of the coverage area of a second overlay network closest to the current overlay network. Divided into first and second areas, as shown in Figure 2. The first area is located between the boundary line and the geographic center of the current coverage area. That is, the first region is generally a region of satisfactory operation. The second area is typically an area of unsatisfactory (relative to the current overlay network) operation. The extent and boundaries of the first and second regions may vary in response to desired system performance, as described below.

Compilation of historical data on geographic sample locations of devices allows identification of long-term trends related to geographic sample locations of devices, for example, consistent positioning on one side or the other of a threshold boundary line. These trends are a more accurate indication of the coverage quality of the wireless communication device.

Returning to FIG. 1 , comparison circuit 108 provides a first decrement control signal in an output on line 118 in response to receiving a geographic sample location of a device in a first area, and comparison circuit 108 responds to receiving a geographic sample location of a device in a second area at A first incremental control signal is provided in an output on line 120 . In some aspects, counting circuit 110 includes subtraction circuit 122 , addition circuit 124 , and accumulator 126 . Subtraction circuit 122 includes an input coupled to the input of the counting circuit on line 118, and includes an output providing a first predetermined output accumulation value on line 128 in response to receipt of the first decrement control signal. Summing circuit 124 includes an input coupled to the input of the counting circuit on line 120, and includes an output providing a second predetermined accumulated value on line 130 in response to receiving the first increment control signal.

Accumulator 126 has inputs connected to lines 128 and 130 , respectively, and an output connected to the output of the counting circuit on line 107 . The accumulator 126 receives the first accumulated value and the second accumulated value, and uses these accumulated values to maintain an accumulation starting with a predetermined initial value. The accumulator 126 subtracts the running total for each first accumulated value, adds the running total for each second accumulated value, and compares the running total to the final value. The output of accumulator 126 provides an exit control signal when the accumulation is greater than or equal to the terminal value, and resets the accumulation to the initial value after the exit control signal is provided.

The final value can be chosen according to the desired system performance. However, the terminal value should be reconciled with the accumulated value. That is, the final value should be large enough such that a second series of accumulated values (from device geographic sample locations in the second area) indicating that there is no consistent location in the second area does not cause the accumulation to be equal to or greater than the final value . Similarly, the final value should be small enough that a second cumulative value representing a longer string consistently positioned in the second region does not cause the cumulative to be equal to or greater than the final value.

One problem associated with compiling historical data of geographic sample locations of equipment is having an accumulated offset of geographic sample locations of equipment in the first region. The accumulated possible offset is a problem because, if the wireless communication device operates in the second area long enough, the accumulated must be able to respond (close to the final value). This is not possible if the wireless communication device has been operating in the first area for a period of time before so many first accumulation values that the accumulation moves too fast to be smaller than the final value.

To avoid drift, accumulator 126 performs a subtraction operation for the accumulation for each first accumulation value only if the accumulation is greater than a predetermined minimum accumulation. Otherwise, the cumulative number remains at the minimum total until a second cumulative value is encountered. As in the case of the threshold boundary and final values, the minimum overall value can be chosen according to the desired performance of the system and in harmony with these other values.

The specified values for the first and second accumulation values can be chosen according to the desired performance of the system. Accumulated values are also coordinated with threshold boundary lines, terminal values, and minimum total values. In one aspect, the absolute value of the first accumulated value is equal to the absolute value of the second accumulated value. That is, the location of the device in the first and second areas is given equal weight in the analysis of when to exit the current coverage area.

Returning to FIG. 2 , the absolute value of the accumulated values in the first and second regions is shown as "1". As an option, unequal weights can be assigned to the accumulated values to bias the operation of the system 100 toward exiting or staying in the current overlay network. For example, assigning a greater weight to the device's geographic sample location in the second area will result in faster exit from the current overlay network because the larger second accumulation value causes the accumulation to increase to the final value more quickly.

Figure 3a is a graphical representation depicting various thresholds and regions between a current overlay network and neighboring overlay networks. Figure 3a is not drawn to scale. The simplified system 100 depicted in FIG. 2 is offset by boundaries. Assigning the same cumulative value to all location points in either the first zone or the second zone does not account for satisfactory variation in equipment operation within the zone and thus does not explain location trends within the zone. For example, in a first region, the system makes no distinction between device locations relatively close to the base station (indicating satisfactory device operation) and relatively close to the threshold boundary (indicating less satisfactory device operation). Accordingly, in certain aspects, predetermined auxiliary threshold boundary lines defining additional regions are included to improve the accuracy and responsiveness of the system. The first auxiliary threshold boundary line defines a first area and a second area as shown in Fig. 3a. The second auxiliary threshold boundary line defines a third area and a fourth area as shown in Fig. 3a. The secondary threshold enables the system to more definitively identify device geosample locations relevant to operation in areas with significantly better or poorer coverage. The auxiliary threshold boundary line as shown in FIG. 3a is parallel to the first threshold boundary line and is the same type of boundary line (straight line) as the first threshold boundary line. However, it can be understood that the system 100 does not limit the first threshold boundary line and the auxiliary boundary line to have similar straight line types, nor does it limit the first threshold boundary line and the auxiliary boundary line to have a parallel structure.

Thus, returning to FIG. 1 , the comparison circuit 108 causes the device geographic sample locations to lie within the first through fourth regions. The comparison circuit 108 then provides: a first decrement control signal for each device geographic sample location in the first region; a second decrement control signal for each device geographic sample location in the third region; an incremental control signal for each device geographic sample location in the second region; and a second incremental control signal for each device geographic sample location in the fourth region.

Subtraction circuit 122 receives first and second decrement control signals on line 118, provides a first accumulation value in response to the first decrement control signal, and provides a third predetermined accumulation value in response to the second decrement control signal. Both accumulations are provided on line 128.

Summing circuit 124 receives the first and second incremental control signals, provides a second accumulated value in response to the first incremental control signal, and provides a fourth predetermined accumulated value in response to the second incremental control signal. Both accumulations are provided on line 130.

Accumulator 126 receives the first, second, third and fourth accumulated values, decreases the accumulation for each of the first and third accumulated values, and increments the accumulation for each of the second and fourth accumulated values. Accumulator 126 decrements the accumulation of each of the first and third accumulation values only if the accumulation is greater than the minimum total value.

The third and fourth accumulation values are greater than the first and second accumulation values, respectively, reflecting the higher certainty associated with the third and fourth regions. Thus, the accumulation moves toward or away from the final value relatively quickly in response to these accumulation values.

Returning to Figure 3a, the choice of auxiliary threshold boundary lines and associated accumulation values can have a large impact on determining when to exit the current coverage area. According to one aspect of the system 100, the first and second auxiliary threshold boundary lines are equidistant from the first threshold boundary line, as shown in FIG. 3a. Then, in one aspect, the absolute value of the third accumulated value is equal to the absolute value of the fourth accumulated value. This gives equal weight to the device's geographic sample location in the third and fourth regions. In FIG. 3a, the third and fourth accumulated values are "3". Alternatively, when the first and second secondary threshold boundary lines are equidistant from the first threshold boundary line, unequal weights may be assigned to the accumulated values such that the operation of the system 100 is directed towards exiting the current overlay network or staying in the current overlay network. Offset in the overlay network. For example, assigning larger weights to values in the fourth region will result in faster exit from the current overlay network because a larger fourth accumulation value causes the accumulation to increase more quickly to the final value.

In some aspects (not shown), the first and second auxiliary threshold boundary lines are unequal distances from the first threshold boundary line. For example, the distance between the first auxiliary boundary line and the first threshold boundary line is larger than the distance between the second auxiliary threshold boundary line and the first threshold boundary line. If the third and fourth accumulation values are equal, less weight is given to the geographic sample location of the device in the area with better coverage (the third area). Alternatively, as described above, the operation of the system 100 may be further biased toward exiting the current overlay network or staying in the current overlay network by assigning unequal third and fourth accumulation values.

Additional auxiliary threshold boundary lines may be added to the system 100 to further fine tune the system. For example, as shown in FIG. 3a, a third auxiliary threshold boundary line may be added to define a fifth area adjacent to the third area. Also as shown in Figure 3a, a fourth auxiliary threshold boundary line may be added to define a sixth region adjacent to the fourth region.

Returning to FIG. 1 , for the device geographic sample locations in the fifth and sixth regions: the comparison circuit 108 provides third decrement and increment control signals, respectively; the subtraction circuit 122 and adder circuit 124 provide fifth and sixth accumulated values, respectively ; and accumulator 126 decrements and increments the accumulated sum in response to the fifth and sixth accumulated values and provides an exit signal, as described above. Typically, the fifth and sixth accumulation values are greater than the third and fourth accumulation values, reflecting the higher certainty associated with the fifth and sixth regions. In FIG. 3a, the absolute value of the fifth and sixth accumulated values is equal to "5". In some aspects, the third and fourth auxiliary threshold boundary lines are equidistant from the first threshold boundary line. However, the above discussion about the selection of accumulation value and auxiliary threshold boundary position in Fig. 3a also applies to this embodiment, therefore, other combinations of accumulation value and auxiliary threshold distance from the first threshold boundary line are also possible. It should be understood that system 100 is not limited to some particular number of thresholds or regions, but that additional auxiliary threshold boundaries may be added.

In some aspects, the number of secondary threshold boundary lines on each side of the first threshold boundary line may not be equal (not shown). For example, only the first auxiliary threshold boundary line may be included. This may result in a slower exit from the current overlay network, since a larger accumulation value relative to the first auxiliary threshold boundary line will rapidly decrease the accumulation away from the final value. However, the discussion above regarding the choice of accumulation values and threshold boundary positions in FIG. 3a also applies to this embodiment, so other combinations and results are also possible.

Figure 3b is a table listing the device locations shown in Figure 3a and the corresponding cumulative adjustments. Returning to FIG. 3 a , there is shown a succession of device geographic sample locations (A through I) to describe the operation of the system 100 . Figure 3b assumes that at point A the minimum total value is zero, the final value is 12, and the accumulation is zero. As shown in Fig. 3b, at point H, the accumulation exceeds the final value, at which point the accumulator (indicated by reference numeral 126 in Fig. 1) issues an exit signal. At point H, the device exits the current overlay network and acquires a neighboring overlay network. At this point, from the perspective of system 100, the previously adjacent overlay network becomes the current overlay network. For example, the geographic sample locations of devices in the second, fourth, and sixth regions now cause the comparator circuit (indicated by reference numeral 108 in FIG. 1 ) to provide decrement control signals, while those in the first, third, and fifth regions The geographic sample location now causes the comparison circuit (indicated by reference numeral 108 in FIG. 1 ) to provide an incremental control signal. Therefore, as shown in Figure 3b, when moving from point H to point I, the accumulation remains at a minimum total value of 0.

Returning to FIG. 1 , in some aspects, the geographic sample location of the device provided by the locator 102 on the line 104 is computed by the locator 102 . In some aspects, a port on line 114 of transceiver 112 receives a geographic sample location of the device calculated from an external location (not shown, such as a base station). The output of transceiver 112 on line 131 provides the position to the input of locator 102 . The locator 102 provides the aforementioned position on the line 104 .

Information provided by device 101 may be used to calculate the device geographic sample location, whether the calculation is performed by locator 102 or by an external source. One method of providing the information is pseudo-ranging using Global Positioning System (GPS) information. Accordingly, in some aspects, locator 102 includes GPS subsystem 132 . GPS subsystem 132 receives GPS location information for wireless device 101 from GPS satellites (not shown). The output of the GPS subsystem 132 is connected to the output of the locator 102 on line 104 for the case where the position is calculated by the locator 102 . In the case of an external position calculated position, the output of the GPS subsystem 132 on line 133 is connected to the output of the locator 102 (which is connected to the input of the transceiver 112). The output of GPS subsystem 132 on line 133 provides pseudorange information. An antenna port on line 114 of transceiver 112 provides pseudorange information for transmission to an external location.

Another way to provide information is network-triangulation, such as Advanced Forward Link Trilateration (AFLT). For this approach, the device 101 uses propagation delays from three different base stations (not shown) to generate information about the device's location. The generation of this information is not shown in FIG. 1 . For the case where the locator 102 calculates the position, the locator 102 uses the network triangulation information to calculate the device geographic sample position and provides this position on the line 104 . For the case of an external location computed position, the antenna port of transceiver 112 on line 114 provides network triangulation information for transmission to the external location.

In certain aspects, system 100 uses a combination of pseudoranging and network triangulation to obtain information about a device's geographic sample location.

In some aspects, system 100 includes reconfiguration subsystem 134 and digital integrated circuit 135 . Reconfiguration subsystem 134 includes system processors for overlay networks such as Code Division Multiple Access (CDMA), Time Division Multiple Access (TDMA), and Global System for Mobile Phones (GSM). Reconfiguration subsystem 134 has an input connected to line 107 and an output on line 136 connected to the input of the digital IC and the input of transceiver 112 . Responsive to receiving an exit control signal on line 107, the reconfiguration subsystem 134 modifies the system processors operating on the current overlay network to operate on a second overlay network, i.e., along a first threshold boundary line opposite to the current overlay network. Neighboring second network. The output of the reconfiguration subsystem on line 136 provides reconfiguration information and instructions for the second network. In response to receiving information and instructions on line 136, transceiver 112 and digital IC 135 reconfigure for the second network.

Calculator 106 has an output on line 137 and comparison circuit 108 has an output connected to the output of calculator 106 on line 137 . In response to the determination of the threshold boundary line, the output of comparison circuit 108 on line 137 provides information about the second overlay network. Reconfiguration subsystem 134 has an input connected to the output of calculator 106 on line 137, and in response to the input reconfiguration subsystem 134 prepares the processor for the current network to be modified to operate on the second overlay network.

In some aspects, reconfiguration subsystem 134 includes storage subsystem 138 to store operating system processor software for overlay networks (eg, CDMA, TDMA, and GSM), and microprocessor 140 . Storage subsystem 138 has an input connected to the output of reconfiguration subsystem 134 on line 137 and in response to the input preselects the operating system processor software corresponding to the overlay network identified in the input on line 137 . Storage circuit 138 has an input connected to the input of reconfiguration subsystem 134 on line 107 and has an output on line 142 . In response to receipt of an exit signal on line 107 , the output of storage subsystem 138 provides on line 142 the preselected operating system processor software. Microprocessor 140 has an input on line 142 and, in response to the input received on line 142, downloads preselected operating system processor software to replace the operating system processor software for the current overlay network. Microprocessor 140 has an output connected to the output of reconfiguration subsystem 134 on line 136 . The output of microprocessor 140 provides reconfiguration information and instructions for the second network in response to downloading preselected operating system processor software.

In some aspects, system 100 includes multiple transceiver and digital IC combinations (not shown) to support overlay networks such as CDMA, TDMA, and GSM, respectively. In these respects, the calculator 106 has an output (not shown) connected to the combination of the transceiver and digital IC, and in response to the accumulator 126 providing an exit signal, the output of the appropriate calculator 106 is provided for use respectively in The transceivers and digital ICs of the current network are deactivated and the signals for the transceivers and digital ICs of the second network are enabled.

In some aspects, the comparison circuit 108 uses a vector referenced to the geographic center of the current overlay network to form the threshold boundary line. These vectors may be stored in a memory subsystem (not shown) in comparison circuit 108 or may be provided in an output on line 116 via transceiver 112 from a base station (not shown). Returning to FIG. 2, in some aspects these vectors may be two geographic points (points A and B) that define the endpoints of a straight threshold boundary line. In some aspects, the vector can be a radius (not shown), and the resulting circular threshold boundary line (not shown) has a radius equal to the length of the vector.

As noted above, threshold boundary lines are generally formed at satisfactory operating boundaries within the current overlay network. However, satisfactory operating boundaries are sensitive to changes in the environmental conditions and/or state of network operation (eg, loss of network signal). For some operating systems (such as TDMA), this boundary is relatively stable. However, in a CDMA cell, the range of satisfactory operation (covering the air range of the network) depends on the traffic load within the cell, as described in the background section. Thus, returning to FIG. 1, in some aspects, the antenna port of transceiver 112 on line 114 receives information from a current network base station (not shown) regarding dynamic conditions in network cells. The output of transceiver 112 on line 116 provides this dynamic condition information, and comparison circuit 108, responsive to receiving this information on line 116, adapts the threshold boundary lines to the dynamic condition. In some aspects, an antenna port on line 114 of transceiver 112 receives information from a current CDMA network base station. Then, for example, modification of the threshold boundary line by comparison circuit 108 may include moving the threshold boundary line closer to the base station in response to a change in cell size due to an increase in traffic load within the cell.

In some aspects, the system 100 can be used to obtain information about the coverage areas of other wireless communication coverage networks (located within, overlapping or adjacent to the current wireless communication coverage network). This may be beneficial when the wireless device is operating in an area where the base station or system 100 does not yet have threshold boundary line information. In particular, the location and coverage area of an intermittent operating system (such as an 802.11 system) can be obtained and stored for future reference. In certain aspects, system 100 prompts a user of device 101 when device 101 enters a known 802.11 coverage area (prompt component not shown), and enables user to switch device 101 from a current overlay network to an 802.11 overlay network (switch component not shown). Once in an 802.11 coverage area, exit from the current coverage area can be achieved by using threshold boundary lines and boundary areas, as described above.

4 is a flow diagram representing a method for determining when to exit a current wireless communication overlay network. Although the method in FIG. 4 (and FIG. 5 below) is represented as a sequence of numbered steps for clarity, these numbers are not sequential unless explicitly stated. It should be understood that some of these steps may be skipped, performed in parallel, or performed sequentially without maintaining a strict sequence. The method begins with step 400 . Step 402 edits the historical record of the device's geographic location data. Step 404 compiles the accumulated data related to the geographic location of the device. Step 406 compares the accumulated data to a predetermined final value. Step 408 then exits from the current overlay network in response to the history of geographic location data. In some aspects, exiting the current overlay network in step 408 includes exiting in response to a base station command from the current overlay network.

FIG. 5 is a flowchart further describing the method shown in FIG. 4 . The method begins with step 500 . Step 502 provides the device geographic location. Step 504 determines threshold boundary lines. Step 506 measures the position of each sample point relative to a predetermined threshold boundary line. Step 508 assigns an accumulation amount to each sample point location. Step 510 executes a mathematical function in response to the measurement of position. Step 512 maintains the cumulative sum. Step 514 divides an area including at least a part of the coverage area of the current overlay network and at least a part of the coverage area of a second overlay network adjacent to the current overlay network into a first area and a second area using a threshold boundary line, the first area and the threshold value The boundary line is adjacent to a first side towards the geographic center of the current overlay network, and the second area is adjacent to a second side of the threshold boundary line. Step 516 decreases the cumulative sum for sample point locations in the first region and increases the cumulative sum for sample point locations in the second region. Step 518 uses the cumulative amount to change the cumulative sum. Step 520 exits when the cumulative sum is greater than or equal to the final value.

In some aspects, providing the device geographic location in step 502 includes periodically providing the device geographic location. In some aspects, providing the geographic location of the device in step 502 includes: the device participating in computing the geographic location of the device. In some aspects, providing the device geographic location in step 502 includes the device receiving the device geographic location from a source external to it.

In some aspects, step 503 compiles information related to the coverage areas of multiple wireless communication coverage networks located within the current wireless communication coverage network, or overlapping with or adjacent to the current wireless communication coverage network. Then, determining the threshold boundary line in step 504 includes: using the edited information to determine the threshold boundary line between the current overlay network and the plurality of overlay networks. In some aspects, compiling coverage-related information for a plurality of wireless communication overlay networks in step 503 includes compiling information for intermittently active overlay networks.

In some aspects, determining the threshold boundary line in step 504 includes: the device of the present invention calculates the threshold boundary line or selects the threshold boundary line from information available in the device. In some aspects, determining the threshold boundary line in step 504 includes the device determining the threshold boundary line based on information received from a source external to the device. In some aspects, determining the threshold boundary line in step 504 includes using a plurality of vectors referenced to the geographic center of the current overlay network to form the threshold boundary line. In some aspects, using the plurality of vectors to form the threshold boundary line includes identifying first and second geographic points using the first and second vectors, respectively, and forming a straight line threshold boundary line between the first and second geographic points. In some aspects, using the plurality of vectors to form the threshold boundary line includes using a third vector to determine a radius and using the length of the third vector as the radius of the circle to form the circular threshold boundary line. In some aspects, forming the threshold boundary line using the plurality of vectors includes receiving the vectors from a base station.

In some aspects, determining the threshold boundary line in step 504 includes adapting the threshold boundary line to dynamic conditions in the overlay network cell. In some aspects, adapting the threshold boundary line to dynamic conditions in an overlay network cell includes adapting the threshold boundary line to dynamic conditions in a CDMA cell. In some aspects, adapting the threshold boundary line to dynamic conditions in a CDMA cell includes adapting the threshold boundary line to inter-cell and intra-cell interference.

In some aspects, measuring the position of each sample point relative to the predetermined threshold boundary line in 506 includes: measuring the first sample point position in the first area, that is, the vertical distance from the first point on the boundary line , and measure a second sample point position in the second area, ie, a second vertical distance from the boundary line. Then, assigning an accumulation amount to each sample point position in step 508 includes: assigning a first accumulation amount to the first sample point position, and assigning a second accumulation amount to the second sample point position. Then, decreasing and increasing the cumulative sum for the sample point locations in the first region in step 516 includes decreasing the cumulative sum using the first accumulation amount, and increasing the cumulative sum using the second accumulation amount. In some aspects, the absolute value of the first accumulation is equal to the absolute value of the second accumulation. In some aspects, the first and second vertical distances are equal.

In some aspects, measuring the position of each sample point relative to the predetermined threshold boundary line in step 506 includes: measuring a plurality of first sample point positions in the first area, and in the plurality of first sample point positions , the third vertical distance between the initial sample point position and the boundary line is greater than the first vertical distance, and the vertical distance between each consecutive position and the boundary line is greater than the vertical distance between the preceding position and the boundary line. In this way, we say that the initial position of the plurality of first sample positions is the position closest to the threshold boundary line, and the subsequent positions of the plurality of first sample positions have increasing distances from the threshold boundary line. In some aspects, measuring the position of each sample point relative to the predetermined threshold boundary line in step 506 includes: measuring a plurality of second sample point positions in the second area, and among the plurality of second sample point positions, initially A fourth vertical distance of the sample point location from the boundary line is greater than the second vertical distance, and a vertical distance of each successive location from the boundary line is greater than a vertical distance of a preceding location. Thus, we say that the initial position of the plurality of second sample positions is the position closest to the threshold boundary line, and subsequent positions of the plurality of second sample positions have increasing distances from the threshold boundary line.

In some aspects, assigning accumulations to each sample point position in step 508 includes: starting from the initial sample point position, assigning a plurality of first successively increasing accumulations to a plurality of first sample points, respectively Each of the locations. Thus, we would like the initial position of the plurality of first sample positions to be assigned the smallest accumulation value, while subsequent positions of the plurality of first sample positions are assigned a greater accumulation amount than the position before it. The value of the initial quantity corresponding to the initial position of the plurality of first sample point positions among the plurality of first accumulation values is greater than the value of the first accumulation quantity, and the value of the plurality of second accumulation values corresponding to the initial position of the plurality of second sample points The value of the initial quantity corresponding to the initial position in the position is greater than the value of the second accumulation quantity. Then, in step 508, assigning an accumulation amount to each sample point position includes: starting from the initial sample point position, assigning a plurality of second continuously increasing accumulation amounts to each of the plurality of second sample point positions Location. Thus, we expect the initial position of the plurality of second sample positions to assign the smallest accumulation value, while subsequent positions of the plurality of second sample positions assign a greater accumulation amount than the position before it. Then, in step 514, respectively decreasing and increasing the cumulative sum for the sample point positions in the first area and the second area includes: reducing the cumulative sum using each of the plurality of first accumulations, and using a plurality of first accumulations Each accumulation amount in the second accumulation amount is reduced by the cumulative sum.

In some aspects, absolute values of accumulations in the plurality of first accumulations are equal to absolute values of corresponding accumulations in the second plurality of accumulations. For example, the same accumulation amount is assigned to each initial position of the plurality of first and second positions. In some aspects, a location in the first plurality of locations is at a vertical distance from the boundary line equal to a corresponding location in the second plurality of locations at a vertical distance from the boundary line. For example, each initial position of the plurality of first and second positions is equidistant from the threshold boundary line. See Figures 1, 2 and 3a for a discussion of weighting positions relative to boundary lines and assigning values to accumulations.

In some aspects, decreasing the cumulative sum in step 516 includes decreasing the cumulative sum if it is greater than a predetermined minimum value.

In some aspects, in step 520, when the accumulated sum is greater than or equal to the final value, exiting the current overlay network includes: after exiting the current overlay network, resetting the accumulated sum to a predetermined initial value.

In some aspects, exiting the current overlay network at step 520 includes entering a second overlay network and reconfiguring the wireless device from the current overlay network operating system processor to the second overlay network operating system server. In some aspects, reconfiguration is accomplished by downloading new software for the second system processor. In some aspects, the reconfiguration is accomplished by switching to new hardware for the second system processor within the wireless device.

A system and method are provided for determining when to exit a current wireless communication overlay network. Embodiments of the present invention may or may not have auxiliary threshold boundary lines, and have multiple device geographic locations relative to the threshold boundary lines. It should be understood, however, that the present invention is not limited to a particular number of secondary threshold boundaries or device geographic locations. The systems and methods are applicable to a wide variety of wireless communication device configurations, as well as to any other device that uses distance from a wireless communication source or the relationship of distance to received energy levels in making a decision. Other modifications and embodiments of the invention will be apparent to those skilled in the art.

While the invention has been described with reference to specific embodiments, these descriptions are only exemplary of the invention's application and should not be taken as limiting. Accordingly, modifications and combinations of features of the disclosed embodiments are within the scope of the invention as defined by the following claims.

Claims (22)

1. one kind is used to determine when the method (500) that withdraws from the current wireless communications coverage network in mobile radio communication apparatus, comprising:

For described Wireless Telecom Equipment provides a plurality of sample points (502), described a plurality of sample points comprise the geographical position of described Wireless Telecom Equipment;

Determine line threshold boundary (504);

Measure the position (506) of each sample point of described a plurality of sample points with respect to described line threshold boundary;

With area dividing is first area and second area (514), described zone comprises at least a portion of first overlay area of described current overlay network and at least a portion of second overlay network adjacent with described current wireless communications coverage network, first side of described line threshold boundary towards the geographic center of described current wireless communications coverage network approached in described first area, and described second area approaches second side of described line threshold boundary;

Reduce the cusum (516) of the measured position of each sample point that is used for described first area;

Increase the cusum (516) of the measured position of each sample point that is used for described second area;

Described cusum and predetermined value are compared (520); And

When described cusum during, withdraw from described current wireless communications coverage network (520) more than or equal to described predetermined value.

2. the method for claim 1 (500) wherein, is measured described each sample point and is comprised with respect to the step of the position of described line threshold boundary: be that described each sample point is assigned accumulation; And,

Wherein, the step of cusum that reduces the measured position of each sample point be used for described first area comprises: use the accumulation of described each sample point to reduce described cusum,

The step of cusum that increases the measured position of each sample point be used for described second area comprises: use the accumulation of described each sample point to increase described cusum.

3. the method for claim 1 (500), wherein, measure described each sample point and comprise with respect to the step of the position of described line threshold boundary:

In described first area, with described line threshold boundary on point measure the first sample point position at a distance of the position of first vertical range;

In described second area, measuring the second sample point position at a distance of the position of second vertical range with described line threshold boundary; And

Be the described first sample point location assignment, first accumulation, and be the described second sample point location assignment, second accumulation;

Wherein, the step that reduces described cusum comprises: use described first accumulation that described cusum is reduced; And

The step that increases described cusum comprises: use described second accumulation that described cusum is increased.

4. method as claimed in claim 3 (500), wherein, measure described each sample point and comprise with respect to the step of the position of described line threshold boundary:

In described first area, measure a plurality of first sample point positions, wherein, first initial sample point position of described a plurality of first sample point positions and described line threshold boundary are at a distance of first vertical range, and the vertical range of each continuous position of described a plurality of first sample point positions and described line threshold boundary is greater than the vertical range of position before it and described boundary line; And

In described second area, measure a plurality of second sample point positions, wherein, second initial sample point position of described a plurality of second sample point positions and described line threshold boundary are at a distance of second vertical range, and the second area vertical range of each continuous second area position of described a plurality of second sample point positions and described line threshold boundary is greater than the second area position before it and the vertical range of described boundary line;

Wherein, be the described first sample point location assignment, first accumulation, and comprise for the step of the described second sample point location assignment, second accumulation:

From the described first initial sample point position, a plurality of first accumulation that increases continuously is assigned to each position in described a plurality of first sample point position respectively; And

From the described second initial sample point position, a plurality of second accumulation that increases continuously is assigned to each position in described a plurality of second sample point position respectively;

Wherein, the step that reduces described cusum comprises:

Use each accumulation in a plurality of first accumulations that described cusum is reduced; And

Increasing described cusum comprises: use each accumulation in a plurality of second accumulations that described cusum is increased.

5. the method for claim 1 (500), wherein, described Wireless Telecom Equipment (101) participates in determining device geographical location.

6. the method for claim 1 (500) wherein, receives described geographical position from described Wireless Telecom Equipment external source.

7. the method for claim 1 (500) wherein, determines that described line threshold boundary comprises: use with the geographic center of described current wireless communications coverage network and form line threshold boundary as a plurality of vectors of benchmark.

8. the method for claim 1 (500) wherein, determines that described line threshold boundary comprises: make described line threshold boundary be adapted to change network coverage condition in the coverage network cell.

9. method as claimed in claim 8 (500), wherein, the network coverage condition that makes described line threshold boundary be adapted to change in the described coverage network cell comprises: be adapted to the dynamic condition in the code division multiple access cell.

10. the method for claim 1 (500) further comprises:

Editor be positioned at described current wireless communications coverage network or overlap or the relevant information in overlay area of adjacent a plurality of wireless communications coverage networks; And

Wherein, determine that described line threshold boundary comprises: the information of using process to edit is determined the line threshold boundary between described current overlay network and the described a plurality of wireless communications coverage network.

11. the method for claim 1 (500), wherein, withdrawing from current wireless communications coverage network zone further comprises: enter second overlay network, and described Wireless Telecom Equipment is reconfigured for the second overlay network operating system processor from current wireless communications coverage network operating system processor.

12. one kind is used to determine when the Wireless Telecom Equipment (101) that withdraws from the current wireless communications coverage network, described Wireless Telecom Equipment comprises:

Locator (102) has the locator output (104) that is configured to the output equipment geographical sample position; And

Calculator (106) links to each other with described locator output (104), and described calculator (106) utilizes the historical record of described device geographical sample position and the first predetermined threshold value boundary line to provide and withdraws from control signal, and described calculator comprises:

Comparison circuit (108), link to each other with described locator output (104), described comparison circuit (108) is configured to selects the first threshold boundary line, the described current overlay network that at least a portion is adjacent with described first threshold boundary line is divided into the first area, second overlay network that at least a portion is adjacent with described first threshold boundary line is divided into second area, measure the difference between each device geographical sample position and the described first threshold boundary line, when device geographical sample position is arranged in described first area, export decrement control signal (118) based on described measurement and when described device geographical sample position is arranged in described second area based on described measurement and output increment control signal (120); And

Counting circuit (110), be configured to and receive described decrement control signal (118) and described increment control signal (120), respond described decrement control signal and described increment control signal carry out mathematical functions, with the result of calculation of mathematical function and predetermined value compares and response ratio provides the described control signal that withdraws from.

13. Wireless Telecom Equipment as claimed in claim 12 (101), wherein, described counting circuit (110) is kept cusum in response to receiving described decrement control signal and increment control signal (120,118), and described cusum and described predetermined value are compared.

14. Wireless Telecom Equipment as claimed in claim 13 (101), wherein, described counting circuit (110) comprising:

Subtraction circuit (122) links to each other with described comparison circuit, and described subtraction circuit is configured to the reception output decrement accumulating value of response to the described first decrement control signal;

Add circuit (124) links to each other with described comparison circuit, and described add circuit is configured to the reception output increment accumulating value of response to the described first increment control signal; And

Accumulator (126) links to each other with described add circuit with described subtraction circuit, and described accumulator is configured to provides the described control signal that withdraws from.

15. Wireless Telecom Equipment as claimed in claim 14 (101), wherein, described accumulator (126) is kept the described cusum that begins from predetermined initial value, reduce the cusum that is used for each decrement accumulating value, increase the cusum that is used for each increment accumulating value, and described cusum and described predetermined value are compared.

16. Wireless Telecom Equipment as claimed in claim 15 (101), wherein, when described cusum during more than or equal to described predetermined value, the described control signal that withdraws from of described accumulator (126) output, and provide described withdraw from control signal after, described cusum is reset to described initial value.

17. Wireless Telecom Equipment as claimed in claim 12 (101) further comprises:

Transceiver (112) links to each other with described comparison circuit (108), and wherein, first threshold boundary line information receives by the antenna port (114) of described transceiver.

18. Wireless Telecom Equipment as claimed in claim 12 (101), wherein, described locator (102) generates the information relevant with the equipment sample position.

19. Wireless Telecom Equipment as claimed in claim 12 (101) further comprises:

Transceiver (112) with antenna port (114), wherein, the antenna port of described transceiver receives the device geographical sample position of being determined by the external source of described Wireless Telecom Equipment (101), and provides described device geographical sample position to described calculator (106).

20. Wireless Telecom Equipment as claimed in claim 12 (101), wherein, described comparison circuit (108) uses a plurality of geographic center with described current wireless communications coverage network to form line threshold boundary as a plurality of vectors of benchmark.

21. Wireless Telecom Equipment as claimed in claim 12 (101) further comprises:

Transceiver (112), be used to receive and be positioned at described current wireless communications coverage network or overlap or the relevant information in overlay area of adjacent other wireless communications coverage network, described transceiver (112) is used for providing the coverage area information that is received to described comparison circuit (108); And

Wherein, described comparison circuit (108) response is determined the line threshold boundary that replaces between described current wireless communications coverage network and described other wireless communications coverage network to the reception of coverage area information.

22. Wireless Telecom Equipment as claimed in claim 12 (101) further comprises:

Transceiver (112);

Digital integrated circuit (135) is operably connected with described transceiver; And

Reconfiguration sub-system (134), link to each other with described calculator (106), described reconfiguration sub-system (134) from described calculator (106) receive described withdraw from control signal and respond the described control signal that withdraws from provide reconfiguration information to described digital integrated circuit (135).

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